1. Field of the Invention
The present invention concerns a device to convert the motion information contained in the video signals of a high-definition television receiver into a motion information signal at the field rate and with the number of lines desired. More particularly, it concerns a device that is used in association with the field rate conversion device for high-definition television receivers as described hereafter.
2. Description of the Prior Art
The field rate conversion device for high definition television receivers as discussed hereinafter enables enabling the conversion of the video signals received at input of a high-definition television receiver, notably decoded HD-MAC 1250/2:1/50 Hz signals or decoded PAL, SECAM or MAC 625/2:1/50 Hz input signals decoded into a high-definition display signal, namely a signal a display with a format of 1250 lines or 900 lines and 2:1 interlacing at a 100 Hz field rate. This field rate conversion device includes a static type input signals processing device and a dynamic (or motion) type input signals processing device. The switching between the dynamic type input signals processing device and the static type input signals processing device is activated by a motion information signal. Should the signals at input of the receiver be formed by HD-MAC 1250/2:1/50 Hz signals, these signals include, in addition to the video information, specific information such as a DATV (digitally assisted television) signal. This DATV signal contains information on the motion or non-motion of the pixels from one field to another. These items of information are therefore used as a motion information signal.
Thus, in the above device, when a field rate conversion of the video signals is done, two types of processing are needed depending on whether the input video signal is of the dynamic type or of the static type. Normally, for static type signals, the processing device carries out a low-pass vertical filtering based on a field while, for the dynamic or moving type signals, the corresponding processing device performs a low-pass vertical filtering based on an image. If a wrong processing is selected, it leads to major errors in the signal which are passed on to the displayed signal. Now, once it is decoded, the DATV signal used for the switching between the two devices gives a signal containing information on the synchronous motion of the 1250/2:1/50 Hz video signal. This signal indicates whether a particular signal should be processed as being static or in motion. However, if it is to be possible for this DATV signal to be used as a motion information signal achieving the switching between the static type processing device and the dynamic type processing device in the field rate conversion device, this signal must be processed so that the motion information is converted into a motion information signal at the field rate and with the number of lines desired.